From the official announcement release, here are the two most pertinent lines:

With PlayStation All-Stars Battle Royale, we set out to make an experience accessible enough for all PlayStation fans to enjoy while also creating something deep enough for the serious fighting game aficionado. We think this "accessible yet deep" strategy is the perfect way to bring PlayStation fans of all stripes together.

and...

The game features a number of cool game modes for both single and multiplayer, with a focus on online play which features a robust tournament mode. Players will be able to compete against each other as well as play cooperatively. We can't wait for you all to try it for yourself.

If you were thinking it might not actually be a Smash Bros. rip-off...well, take a look at the trailer above.